81565065704 has 16 divisors (see below), whose sum is σ = 153056962500. Its totient is φ = 40749875712.

The previous prime is 81565065683. The next prime is 81565065707. The reversal of 81565065704 is 40756056518.

It can be written as a sum of positive squares in 2 ways, for example, as 81196502500 + 368563204 = 284950^2 + 19198^2 .

It is not an unprimeable number, because it can be changed into a prime (81565065707) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4071527 + ... + 4091510.

Almost surely, 2^81565065704 is an apocalyptic number.

It is an amenable number.

81565065704 is a deficient number, since it is larger than the sum of its proper divisors (71491896796).

81565065704 is a wasteful number, since it uses less digits than its factorization.

81565065704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8164292 (or 8164288 counting only the distinct ones).

The product of its (nonzero) digits is 1008000, while the sum is 47.

The spelling of 81565065704 in words is "eighty-one billion, five hundred sixty-five million, sixty-five thousand, seven hundred four".